Many engineering applications require a constant operating force to safely interact with specific objects and prevent damage or destruction. This paper presents a compact constant-force mechanism (CFM) based on a novel architecture. The proposed design leverages the stiffness combination principle, integrating a negative-stiffness mechanism with a positive-stiffness element to achieve a near-constant force output. The negative stiffness is provided by a V-shaped bistable beam arranged in a parallel configuration, while the positive stiffness is contributed by a nested spring-like beam. As a fully compliant system, the mechanism benefits from advantages such as frictionless motion, cost-effectiveness, high precision, and scalability. These features make it well-suited for applications in soft robotic end-effectors, micro-electro-mechanical systems (MEMS), surgical tools, and biomedical devices. Finite element analysis (FEA) was employed for modeling, design, and validation of the mechanism’s performance.